1. Field of the Invention
The present invention relates to a blade mechanism which has a plurality of blades to form an aperture.
2. Description of the Related Art
Conventionally, a blade mechanism provided in a camera has a plurality of blades which form an aperture. The blades have a driving pin and a pivot. The blades are rotated around the pivot by a driving mechanism which drives the driving pins. The size of the aperture is changed by the rotation of the blades.
However, the rotating position of the blades cannot be set accurately, because the range of movement of the blades is relatively large compared to the range of movement of the driving pin since the pivot and the driving pin are placed close to each other. Therefore, it is difficult to set the size of the aperture precisely.
On the other hand, there are some blade mechanisms in which the number of blades is increased in order to set the aperture more accurately. However, in such devices, the iris can not be closed completely, because the blades block each other.